Feature: Add LapseRate extensions

[jnyrup]

This PR extends LapseRate with four operator overloads:

• TemperatureDelta / LapseRate -> Length
• Temperature / LapseRate -> Length
• Length * LapseRate -> TemperatureDelta
• LapseRate * Length -> TemperatureDelta

[0xferit]

Welcome and thanks for the contribution. I couldn't find any errors but let's wait for @angularsen for merging.

[jnyrup]

What are your gut feelings about the Temperature / LapseRate -> Length?
Will it cause more harm than good based on previous confusion related to the difference between Temperature and TemperatureDelta.

And similar, how about conversions to LapseRate?

I think TemperatureDelta / Length -> LapseRate makes perfect sense, while Temperature / Length -> LapseRate might too ambiguous?

For consistency I could imagine we wanted to either only use TemperatureDelta or use Temperature in both conversions from and to LapseRate.

Any preferences on whether TemperatureDelta / Length -> LapseRate is an extension to TemperatureDelta or Length?

[angularsen]

If I understand correctly, I think Temperature cannot be used for the same reason you can't add two temperatures, you can only add a delta (range on scale) to a temperature (point on scale) or add two deltas to get a new larger delta.

LapseRate [▲°C/m] describes the gradient for how much the temperature changes (delta) over a distance, so the proposed equation becomes:

TemperatureDelta [▲°C] / LapseRate [▲°C/m] = 
TemperatureDelta [▲°C] / (TemperatureDelta [▲°C] / Length [m]) = 
Length [m]

In hindsight, LapseRate abbreviation should probably be changed to reflect this? It is currently missing the delta symbol. But not sure if this goes against the convention in the domain.

Any preferences on whether TemperatureDelta / Length -> LapseRate is an extension to TemperatureDelta or Length?

I would say TemperatureDelta, because it is the leading quantity.

[angularsen]

I vote to drop this.

[angularsen]

If this is removed, I think this PR is good to go.

[jnyrup]

Thanks for the review.
I've updated the PR with two changes:

• removed the Temperate / LapseRate -> Length
• added TemperatureDelta / Length -> LapseRate

Regarding the abbreviation:

• Currently it is °C/m for LapseRateUnit.DegreeCelsiusPerKilometer, which is wrong due to a missing a k.
• ▲°C/km would be fine with me.

[0xferit]

@jnyrup About missing k, yeah I did implement that and when I changed base unit forgot to change the abbreviation also, my bad.

And yeah, we should change the abbreviation to ▲°C/km

[jnyrup]

And related, why do we use ▲ instead of ∆?

[0xferit]

I'm not aware of a specific reason for using ▲. I used ▲ because @angularsen used it in his comment above. Let's wait for his answer.

[angularsen]

No preference for me other than it already being used for TemperatureDelta, I suppose ∆ is more correct.

[0xferit]

Hmm, then I'm opening an issue for replacing every occurrence of ▲ with ∆ in the library, for the sake of consistency.

I also see some minor differences in code-style in various places (talking in general, not about this p.r.). Perhaps we can set a standard on this and write it to the wiki. Standards make contributing less confusing and reviewing less difficult, I believe.

[angularsen]

That would be good! And maybe adding it as a contribution guideline so it pops up whenever someone creates a new issue / PR.

[jnyrup]

I've updated the PR so the unit of lapse rate is now ▲°C/km.

[angularsen]

@jnyrup Shouldn't we use the new delta symbol? Per #328 .

[jnyrup]

I thought that was the job of #327?

[angularsen]

Sure, but if you are already modifying the abbreviation here, why not use the correct symbol to begin with?
If you change the symbol, this PR is ready to merge.

[jnyrup]

The PR has been updated with the correct delta symbol.
Thanks for the fast reviews!

[angularsen]

Thanks! Nuget 3.81 is out.